package com.cuit.spring.config;

import cn.hutool.core.util.StrUtil;
import cn.hutool.jwt.JWTException;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.cuit.spring.common.Constants;
import com.cuit.spring.exception.ServiceException;
import com.cuit.spring.service.IUserService;
import com.cuit.spring.entity.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Slf4j
public class JwtInterceptor implements HandlerInterceptor {

    @Autowired
    private IUserService userService;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws Exception{
        String token = request.getHeader("token");
        //如果不是映射到方法直接通过
        if(!(handler instanceof HandlerMethod)){
            return true;
        }

        //执行认证
        if(StrUtil.isBlank(token)){
            log.error("无token");
            throw new ServiceException(Constants.CODE_401,"无token，请重新登录");
        }

        //获取token中的user id
        String userId;
        try{
            userId = JWT.decode(token).getAudience().get(0);
        }catch (JWTException jwtException){
            log.error("token验证失败");
            throw new ServiceException(Constants.CODE_401,"token验证失败");
        }

        //根据token中的user id查询数据库
        User user = userService.getById(userId);
        if(user == null) {
            log.error("用户不存在");
            throw new ServiceException(Constants.CODE_401, "用户不存在，请重新登录");
        }

        //用户密码加签验证 token
        JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(user.getPassword())).build();
        try{
            jwtVerifier.verify(token);
        }catch (JWTVerificationException e){
            log.error("token验证失败");
            throw new ServiceException(Constants.CODE_401,"token验证失败，请重新登录");
        }

        return true;
    }
}
